Area Forecast Discussion
Issued by NWS Medford, OR

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KMFR 261124
AFDMFR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MEDFORD OR
324 AM PST MON JAN 26 2015

.DISCUSSION...AS OF 3 AM PST THE SATELLITE IMAGERY SHOWS FOG HAS
FORMED IN THE I-5 CORRIDOR FROM NORTHERN DOUGLAS COUNTY THROUGH
THE ROGUE VALLEY. FOG CAN ALSO BE SEEN IN THE ILLINOIS VALLEY, THE
APPLEGATE VALLEY AND THE KLAMATH RIVER VALLEY AND SCOTT VALLEY IN
NORTHERN CALIFORNIA. THIS IS IN LINE WITH PREVIOUS FORECAST AS WE
ARE STILL UNDER THE INFLUENCE OF THE STRONG RIDGE. I HAVE ISSUED A
DENSE FOG ADVISORY AND HAVE TO TIME THE ONSET OF THE DENSE FOG
CLOSER TO SUNRISE OR AROUND 6AM. TIMING AND DURATION WILL BE
SIMILAR TO WHAT HAS BEEN HAPPENING THE LAST FEW DAYS. FOG MAY
AGAIN BE QUITE PERSISTENT IN THE GRANTS PASS AREA TODAY.

THE RIDGE WEAKENS SLIGHTLY TODAY AND TIMEHEIGHTS OF THE AREA SHOWS
TEMPERATURES AT 850MB COMING DOWN FROM YESTERDAY WITH THE FORECAST
CALLING FOR MORE COOLING TUESDAY AND WEDNESDAY. THE WEAKENING
RIDGE ALLOWS UPSTREAM FRONT TO APPROACH COOS AND DOUGLAS COUNTY.
AT THE SAME TIME THERE IS A CLOSED LOW THAT WILL BE MOVING NORTH
ACROSS CENTRAL CALIFORNIA AT THE SAME TIME. THE MOISTURE FROM
THIS LOW PRESSURE WILL BRING RAIN CHANCE TO SOUTHERN SISKIYOU AND
MODOC COUNTY TUESDAY AFTERNOON THROUGH TUESDAY NIGHT. RAINFALL
AMOUNT WITH THESE TWO SEPARATE SYSTEMS WILL BE VERY LIGHT..MORE
LIGHT SHOWERS AND MORE CLOUD COVER. THE LOW PRESSURE APPROACHING
FROM THE SOUTH IS EXPECTED TO BECOME AN OPEN TROUGH AS IT TRACKS
INTO NEVADA. LIGHT SHOWERS MAY LINGER ACROSS NORTHERN DOUGLAS
COUNTY AND POSSIBLE IN THE CRATER LAKE AREA ON WEDNESDAY BUT NO
RAIN IS EXPECTED FOR MEDFORD.

THE CURRENT AIR STAGNATION ADVISORY RUNS THROUGH TUESDAY MORNING.
WE WILL NEED TO EVALUATE IF THE DISTURBANCE IS ENOUGH TO BREAK THE
INVERSION BY TUESDAY AFTERNOON. HOWEVER A RIDGE IS EXPECTED TO
NOSE INTO OUR AREA FROM THE EASTERN PACIFIC THURSDAY. /FB


&&

.AVIATION...BASED ON THE 26/06Z TAF CYCLE...SATELLITE SHOWS STRATUS
ABOUT 25 MILES OFF THE COAST THIS EVENING, AND ALTHOUGH MODELS BRING
IT NEAR THE NORTH COAST BY AROUND 26/12Z, CURRENT BEHAVIOR OF THE
DECK WOULD SUGGEST IT STAYS OFFSHORE THROUGH THE NIGHT.  HOWEVER,
FOG/STRATUS WITH IFR CIGS/MVFR VIS MAY FORM LOCALLY ALONG THE COAST
PRIOR TO SUNRISE, AND WHAT DOES FORM WILL LIKELY BURN OFF FAIRLY
QUICKLY MONDAY MORNING. FOG WITH LIFR CIGS/VIS IS EXPECTED TO FORM
IN WEST SIDE VALLEYS AGAIN BEFORE DAWN MONDAY AND LAST THROUGH LATE
MORNING. ELSEWHERE, VFR CONDITIONS WILL CONTINUE FOR THE NEXT 24
HOURS. -BPN/WRIGHT

&&

.MARINE...UPDATED AT 745 PM SUNDAY 25 JANUARY 2015...SWELL HAS NOT
BEEN AS HIGH AS EXPECTED THIS EVENING AND WILL CONTINUE TO DIMINISH
TONIGHT, SO THE SMALL CRAFT ADVISORY HAS BEEN DROPPED. SOUTH WINDS
WILL INCREASE THROUGH MONDAY AS A LOW PRESSURE MOVES BY TO THE
NORTH, HOWEVER WINDS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS.
A WEAK FRONT MOVES OVER THE WATERS TUESDAY AND THEN DISSIPATES OVER
THE AREA ON WEDNESDAY WHICH WILL LEAD TO LIGHT AND VARIABLE WINDS
DURING THE PERIOD. MODERATE NORTHERLY WINDS ARE EXPECTED THURSDAY
INTO FRIDAY AS HIGH PRESSURE BUILDS IN TO THE NORTH. -WRIGHT

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...AIR STAGNATION ADVISORY UNTIL 11 AM PST TUESDAY FOR
     ORZ023-024-026-616-620-622.
     DENSE FOG ADVISORY FROM 6 AM TO 10 AM PST THIS MORNING FOR
     ORZ023-024-026-616-620-622.
     AIR STAGNATION ADVISORY UNTIL 11 AM PST TUESDAY FOR
     ORZ029>031-623>625.

CA...NONE.

PACIFIC COASTAL WATERS...NONE.

$$

FJB/FJB/DW


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.